Conventional motors include a motor disclosed in, for example, the specification of U.S. Pat. No. 5,245,258. The motor includes a motor main body including a rotary shaft, a gear housing, which accommodates a reduction gear for reducing the rotation speed of the rotary shaft, and a control circuit member. The gear housing is integrated with the motor main body. The control circuit member is accommodated in a circuit accommodating portion provided in the gear housing. The control circuit member includes a circuit substrate, on which a rotation detecting element (such as a Hall IC) for detecting rotation information of the rotary shaft is mounted. The circuit substrate includes an element mounting portion for mounting the rotation detecting element (such as a Hall IC) on the circuit substrate. The rotation detecting element needs to be arranged at a position near a detector magnet that is provided on and rotates integrally with the rotary shaft, and at a position facing the magnet. Thus, the element mounting portion of the circuit substrate extends to the vicinity of the detector magnet. The circuit substrate is assembled to the circuit accommodating portion of the gear housing by inserting the circuit substrate along the extending direction of the element mounting portion (perpendicular to or inclined with respect to the axial direction of the rotary shaft).
However, in the above-mentioned motor, the circuit substrate is assembled to the circuit accommodating portion of the gear housing along the direction perpendicular to or inclined with respect to the axial direction of the rotary shaft, whereas the motor main body and the gear housing are assembled along the axial direction of the rotary shaft. Thus, the assembly of the circuit substrate to the circuit accommodating portion is complicated.